Epigenetic Markers of Colorectal Cancer: Clinical Data Analysis

Abstract

The aim of the study was to systematize the results of clinical application of epigenetic biomarkers "microRNA" and "DNA methylation" in early diagnosis and prognosis in patients with colorectal cancer. Material and methods. Data review was conducted by the keywords "colorectal cancer" with "miRNA" or "methylation" in PubMed, Cochrane Library, ScienceDirect, ELECTRONIC LIBRARY and was limited by the period 2016-2021. In addition, a manual search for articles in peer-reviewed journals was performed. Exclusion criteria were: description of separate clinical cases; books and documents; experimental oncology in laboratory animals, comparison of therapeutic results of patients receiving chemotherapy. Out of 139 initially identified, 37 sources were included in the final analysis, of which 20 meta-analyzes, 1 randomized clinical trial, 14 systematic reviews and 2 practical guidelines. Results. Based on the analysis of clinical data, it has been established that the optimal environment for miR isolation for early diagnosis of colorectal cancer is the intestinal wall, furthermore, miR-139 has a proven diagnostic value. At the later stages of tumor development, fecal miRs, namely miR-21, can also be used as a screening method. MiR-181a, miR-181b, miR-20a, miR-10b and miR-145 are highly sensitive predictors of overall survival in colorectal cancer patients. They can potentially be considered as prognostic biomarkers and as decisions when administering adjuvant chemotherapy. miR21, miR106a, miR143, miR 150 and miR215 are most commonly used in clinical practice to determine the prognosis of treatment. Tumor and paratumor tissues can also be differentiated from the normal colon tissue in a healthy person by methylation of the SFRP2, SFRP1, TFPI2, BMP3, NDRG4, SPG20, BMP3 and NDRG4, SFRP1, 2, 4, 5, hMLH1 and RASSF1A genes. The analysis of methylated SEPT9 genes is the most informative of them: an increased weight of the mitylated SEPT9 gene directly correlates with progression and low tumor differentiation in patients with colorectal cancer. Conclusion. Literature data confirm that changes in the concentration of microRNA and methylated DNA in the environments of the human body correlate with the risk of oncogenesis, progression and invasion of colorectal cancer. It is reasonable to use a diagnostic algorithm differentiated by the analyzed tissues (blood, intestinal tissue, feces, urine), the expected stage of tumor development, diagnostic tasks (screening, survival prognosis) for the effective use of epigenetic markers of colorectal cancer in the clinical practice.